Leak shuts Sellafield plant for four weeks
The company revealed that an 'engineering fault' caused the leak but said this has not been identified.
This is because the leak took place inside a sealed concrete- lined unit where liquid plutonium is evaporated to form a solid oxide for storage.
A spokesman for BNFL said that in the first few hours after the leak, plant managers decided they could deal with it on their own, within a few days.
But once they realised the amount of plutonium liquid involved in the incident, the managers decided that the clean-up would need approval from the Nuclear Installations Inspectorate.
The company said no radioactive material escaped after the leak on 8 September, but its workers cannot enter the unit until the NII gives its approval for the clean-up to go ahead.
BNFL is still finalising its recovery proposals and expects to submit these to inspectors within the next few days.
The company said the four- week shut down would not cost them any money because it would not affect the reprocessing contracts it held with customers.
'It will just be a case of catch up when we start again,' a spokeswoman said.
'There is fuel in the plant waiting to be reprocessed, but the business is already there. We have plenty of storage room.'
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